This invention relates in general to anti-lock brake systems and in particular an algorithm for verification that the anti-lock brake system control module installed in a particular vehicle corresponds to the configuration of the vehicle drive train.
An Anti-lock Brake System (ABS) is often included as standard or optional equipment on new vehicles. When actuated, the ABS is operative to control the operation of some or all of the vehicle wheel brakes. A typical ABS includes a plurality of solenoid valves mounted within a control valve and connected to the vehicle hydraulic brake system. Usually, a separate hydraulic source, such as a motor driven pump, is included in the ABS for reapplying hydraulic pressure to the controlled wheel brakes during an ABS braking cycle. An ABS further includes an electronic control module which is electrically connected to wheel speed sensors mounted adjacent to the controlled wheels, the solenoid valves and pump motor. The control module can be mounted directly upon the control valve or located remotely therefrom. The control module includes a microprocessor, or ABS controller, which is programmed to control the ABS in accordance with a control algorithm and parameters permanently stored in a Read Only Memory (ROM). The microprocessor also can access a Random Access Memory (RAM) for temporary storage and retrieval of data.
During vehicle operation, the microprocessor in the ABS control module continuously receives speed signals from the wheel speed sensors. The microprocessor monitors the speed signals for potential wheel lock-up conditions. When the vehicle brakes are applied and the microprocessor senses an impending wheel lock-up condition, the microprocessor is responsive thereto to close a power relay. The power relay controls the supply of electric power to enable the solenoid valves and actuate the pump motor. The microprocessor selectively actuates the solenoid valves in the control valve in accordance with the control algorithm stored in the ROM to cyclically relieve and reapply hydraulic pressure to the controlled wheel brakes. The hydraulic pressure applied to the controlled wheel brakes is adjusted by the operation of the solenoid valves to limit wheel slippage to a safe level while continuing to is produce adequate brake torque to decelerate the vehicle.